Study reveals the science of the “wet dog shake”

A dog can shake up to 70 percent of the water from its fur in only four seconds. (Photo credit: Georgia Tech)

Georgia Tech researchers David Hu, Zachary Mills, and Andrew Dickerson set out to understand the science behind how many mammals — including the domestic dog — shake in order to dry themselves when wet.

In nature, survival sometimes depends on how quickly a mammal can dry himself. What Hu, Mills, and Dickerson prove is that when a dog shakes himself dry, he is preventing hypothermia in an extremely energy-efficient way.

One thing that the researchers discovered is that the smaller the mammal, the faster it must shake to exert the ideal amount of force on the water droplets. For example, a mouse must shake at a rate of 30 times per second, a cat nine times per second, and a Labrador Retriever only four times per second.

“The largest animal is 10,000 times heavier than the smallest animal,” Hu told The Atlantic, “but the forces on the drops are basically constant across all these mammals.”

Another interesting tidbit the study revealed is that a dog can shake up to 70 percent of the water from its fur in only four seconds — something to think about the next time your pup shakes after his bath.

Why study the particulars of the “wet dog shake”?

“Engineers are interested in new kinds of ideas and any type of animal that is a champion of something,” Hu explained during an interview for The Atlantic. “Dogs are good at getting dry. Any time an animal is really good at something, there is an idea there that can be used.”

Dickerson explained that understanding how dogs and other mammals dry themselves could eventually lead to improved performance and self-cleaning features for robotics. “We hope the findings from our research will contribute to technology that can harness these efficient and quick capabilities of drying seen in nature,” he told ScienceBlog.com.